/* ==========================================================================
   InteFlow — new UI layer
   Loaded after assets/site.css. It does not change markup contracts or JS
   hooks: it remaps the design tokens and restyles the shared shell.

   Day (default)  : warm paper, olive accent text, lime fill
   Night          : warm near black, lime accent
   ========================================================================== */

/* ---------------------------------------------------------------- tokens -- */

:root {
  /* spacing + shape */
  --r-1: 8px;
  --r-2: 12px;
  --r-3: 16px;
  --r-4: 24px;
  --s-1: 4px;
  --s-2: 8px;
  --s-3: 12px;
  --s-4: 16px;
  --s-5: 24px;
  --s-6: 32px;
  --s-7: 48px;
  --s-8: 64px;
  --s-9: 96px;

  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --tone: 400ms;

  /* type */
  --font-ui: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC",
    sans-serif;
  --font-display: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC",
    sans-serif;
  --font-mono: "SF Mono", ui-monospace, SFMono-Regular, Menlo, Consolas,
    "Liberation Mono", monospace;
  --wrap: 1120px;
}

/* day */
[data-theme="light"] {
  --ui-bg: #faf8f3;
  --ui-bg-2: #f3f1ea;
  --ui-surface: #ffffff;
  --ui-surface-2: #f5f3ec;
  --ui-surface-3: #eae7dd;
  --ui-line: #e4e1d7;
  --ui-line-strong: #cfcbbe;

  --ui-ink: #0d0d0c;
  --ui-ink-2: #3f3f3a;
  --ui-muted: #6e6e67;
  --ui-faint: #8a8a82;

  --ui-accent: #cdf25b;         /* fill only */
  --ui-accent-ink: #0d0d0c;     /* text on the fill */
  --ui-accent-text: #4f6b10;    /* accent as text / icon */
  --ui-accent-soft: rgba(205, 242, 91, 0.32);
  --ui-accent-line: #a8c63c;

  --ui-nav: rgba(255, 255, 255, 0.76);
  --ui-shadow: 0 8px 32px rgba(24, 22, 16, 0.1);
  --ui-shadow-sm: 0 2px 10px rgba(24, 22, 16, 0.06);
  --ui-grad: linear-gradient(90deg, #0d0d0c 0%, #6e6e67 100%);
  --ui-grid: rgba(13, 13, 12, 0.05);
  --ui-selection: #cdf25b;

  /* legacy token remap: keeps untouched components consistent */
  --paper: var(--ui-bg);
  --paper-2: var(--ui-bg-2);
  --paper-3: var(--ui-surface-3);
  --surface: var(--ui-surface);
  --ink: var(--ui-ink);
  --ink-2: var(--ui-ink-2);
  --muted: var(--ui-muted);
  --faint: var(--ui-faint);
  --line: var(--ui-line);
  --line-strong: var(--ui-line-strong);
  --accent: var(--ui-accent-text);
  --accent-dark: #3c5309;
  --accent-soft: var(--ui-accent-soft);
  --blue: #2f4bb8;
  --dark: #131209;
  --dark-2: #1f1f1f;
  --dark-line: #313131;
  --dark-text: #ffffff;
  --dark-muted: #a3a39c;
  --ok: #4f8f2f;
}

/* night */
[data-theme="dark"] {
  --ui-bg: #131209;
  --ui-bg-2: #181818;
  --ui-surface: #1f1f1f;
  --ui-surface-2: #272727;
  --ui-surface-3: #313131;
  --ui-line: #313131;
  --ui-line-strong: #3e3e3b;

  --ui-ink: #ffffff;
  --ui-ink-2: #d9d9d3;
  --ui-muted: #a3a39c;
  --ui-faint: #8a8a85;

  --ui-accent: #cdf25b;
  --ui-accent-ink: #0d0d0c;
  --ui-accent-text: #cdf25b;
  --ui-accent-soft: rgba(205, 242, 91, 0.16);
  --ui-accent-line: rgba(205, 242, 91, 0.45);

  --ui-nav: rgba(31, 31, 31, 0.72);
  --ui-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
  --ui-shadow-sm: 0 2px 10px rgba(0, 0, 0, 0.35);
  --ui-grad: linear-gradient(90deg, #ffffff 0%, #9b9b9b 100%);
  --ui-grid: rgba(255, 255, 255, 0.05);
  --ui-selection: #cdf25b;

  --paper: var(--ui-bg);
  --paper-2: var(--ui-bg-2);
  --paper-3: var(--ui-surface-3);
  --surface: var(--ui-surface);
  --ink: var(--ui-ink);
  --ink-2: var(--ui-ink-2);
  --muted: var(--ui-muted);
  --faint: var(--ui-faint);
  --line: var(--ui-line);
  --line-strong: var(--ui-line-strong);
  --accent: var(--ui-accent-text);
  --accent-dark: #d9fa78;
  --accent-soft: var(--ui-accent-soft);
  --blue: #8fb0ff;
  --dark: #1f1f1f;
  --dark-2: #272727;
  --dark-line: #313131;
  --dark-text: #ffffff;
  --dark-muted: #b4b4b4;
  --ok: #9ad46b;
}

/* ------------------------------------------------------------------ base -- */

html {
  scroll-padding-top: 104px;
  background: var(--ui-bg);
}

body {
  background: var(--ui-bg);
  color: var(--ui-ink);
  font-family: var(--font-ui);
  font-size: 15px;
  line-height: 1.7;
  transition: background-color var(--tone) var(--ease), color var(--tone) var(--ease);
}

::selection {
  background: var(--ui-selection);
  color: #0d0d0c;
}

:focus-visible {
  outline: 2px solid var(--ui-accent-text);
  outline-offset: 3px;
  border-radius: 6px;
}

h1,
h2,
h3,
h4 {
  font-family: var(--font-display);
  font-weight: 600;
  letter-spacing: -0.02em;
  text-wrap: balance;
}

p {
  text-wrap: pretty;
}

a {
  color: var(--ui-ink);
}

code,
.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

code {
  padding: 1px 5px;
  border: 1px solid var(--ui-line);
  border-radius: 6px;
  background: var(--ui-surface-2);
  color: var(--ui-ink-2);
  font-size: 0.9em;
}

.wrap {
  width: min(var(--wrap), calc(100% - 48px));
}

.skip-link {
  background: var(--ui-ink);
  color: var(--ui-bg);
  border-radius: var(--r-1);
}

.scroll-progress {
  background: transparent;
}

.scroll-progress span {
  background: var(--ui-accent-text);
}

/* surfaces that must survive the theme switch */
.card,
.platform-card,
.home-highlight,
.principle,
.flow-card,
.core-card,
.install-card,
.theme-choice,
.arch-node,
.faq-item,
.number-item,
.demo-shell,
.closing-inner,
.rule-card,
.step,
.feature-group {
  transition: background-color var(--tone) var(--ease),
    border-color var(--tone) var(--ease), color var(--tone) var(--ease),
    transform 300ms var(--ease), box-shadow var(--tone) var(--ease);
}

/* ---------------------------------------------------------------- header -- */

.site-header {
  position: fixed;
  top: 16px;
  left: 0;
  right: 0;
  z-index: 120;
  background: transparent;
  border-bottom: 0;
  padding: 0 24px;
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
}

.site-header.is-scrolled {
  background: transparent;
  border-bottom-color: transparent;
}

.site-header .header-inner {
  width: fit-content;
  max-width: var(--wrap);
  margin: 0 auto;
  min-height: 52px;
  gap: 24px;
  padding: 8px 8px 8px 16px;
  background: var(--ui-nav);
  border: 1px solid var(--ui-line);
  border-radius: var(--r-3);
  box-shadow: var(--ui-shadow);
  backdrop-filter: blur(16px) saturate(140%);
  -webkit-backdrop-filter: blur(16px) saturate(140%);
}

.brand {
  gap: 8px;
}

.brand-mark {
  width: 26px;
  height: 26px;
  border-radius: 7px;
}

.brand-text strong {
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.brand-text small {
  margin-top: 1px;
  font-size: 8px;
  letter-spacing: 0.14em;
  color: var(--ui-faint);
}

.site-nav {
  gap: 2px;
  margin-left: auto;
}

.site-nav a {
  padding: 8px 12px;
  border-radius: var(--r-1);
  color: var(--ui-muted);
  font-size: 13.5px;
  font-weight: 500;
  transition: color 200ms var(--ease), background-color 200ms var(--ease);
}

.site-nav a::after {
  display: none;
}

.site-nav a:hover,
.site-nav a.is-active,
.site-nav a[aria-current="page"] {
  color: var(--ui-ink);
  background: var(--ui-surface-2);
}

.header-actions {
  gap: 4px;
}

.ghost-link {
  padding: 8px 10px;
  border-radius: var(--r-1);
  color: var(--ui-muted);
  font-size: 13px;
  transition: color 200ms var(--ease), background-color 200ms var(--ease);
}

.ghost-link:hover {
  color: var(--ui-ink);
  background: var(--ui-surface-2);
}

.lang-switch {
  min-width: 34px;
  height: 30px;
  padding: 0 8px;
  border: 1px solid var(--ui-line);
  border-radius: var(--r-1);
  color: var(--ui-muted);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  transition: color 200ms var(--ease), border-color 200ms var(--ease),
    background-color 200ms var(--ease);
}

.lang-switch:hover {
  color: var(--ui-ink);
  border-color: var(--ui-line-strong);
  background: var(--ui-surface-2);
}

/* theme toggle */
.theme-btn {
  position: relative;
  width: 34px;
  height: 30px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 0;
  border-radius: var(--r-1);
  background: transparent;
  color: var(--ui-muted);
  cursor: pointer;
  transition: color 200ms var(--ease), background-color 200ms var(--ease);
}

.theme-btn:hover {
  color: var(--ui-ink);
  background: var(--ui-surface-2);
}

.theme-btn:active {
  transform: scale(0.94);
}

.theme-btn svg {
  position: absolute;
  transition: transform 500ms var(--ease), opacity 300ms var(--ease);
}

[data-theme="light"] .ic-sun {
  opacity: 0;
  transform: rotate(-90deg) scale(0.5);
}

[data-theme="light"] .ic-moon {
  opacity: 1;
  transform: rotate(0) scale(1);
}

[data-theme="dark"] .ic-sun {
  opacity: 1;
  transform: rotate(0) scale(1);
}

[data-theme="dark"] .ic-moon {
  opacity: 0;
  transform: rotate(90deg) scale(0.5);
}

.menu-btn {
  width: 32px;
  height: 30px;
  border-radius: var(--r-1);
  transition: background-color 200ms var(--ease);
}

.menu-btn:hover {
  background: var(--ui-surface-2);
}

.menu-btn span {
  background: var(--ui-ink);
}

/* --------------------------------------------------------------- buttons -- */

.btn {
  padding: 9px 14px;
  border: 1px solid transparent;
  border-radius: var(--r-1);
  font-family: var(--font-ui);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0;
  line-height: 1.2;
  transition: background-color 200ms var(--ease), color 200ms var(--ease),
    border-color 200ms var(--ease), transform 200ms var(--ease),
    box-shadow 200ms var(--ease);
}

.btn-small {
  padding: 8px 12px;
  font-size: 13px;
}

.btn-ink {
  background: var(--ui-ink);
  color: var(--ui-bg);
  border-color: var(--ui-ink);
}

.btn-ink:hover {
  background: var(--ui-ink);
  border-color: var(--ui-ink);
  color: var(--ui-bg);
  transform: translateY(-1px);
  box-shadow: var(--ui-shadow-sm);
}

.btn-accent {
  background: var(--ui-accent);
  border-color: var(--ui-accent);
  color: var(--ui-accent-ink);
}

.btn-accent:hover {
  background: var(--ui-accent);
  border-color: var(--ui-accent);
  color: var(--ui-accent-ink);
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(205, 242, 91, 0.22);
}

.btn-outline {
  background: transparent;
  border-color: var(--ui-line-strong);
  color: var(--ui-ink);
}

.btn-outline:hover {
  background: var(--ui-surface-2);
  border-color: var(--ui-line-strong);
  color: var(--ui-ink);
  transform: translateY(-1px);
  box-shadow: none;
}

.btn:active {
  transform: scale(0.98);
}

.text-link {
  color: var(--ui-ink);
  font-size: 13.5px;
  font-weight: 500;
  text-decoration: none;
  border-bottom: 1px solid var(--ui-line-strong);
  padding-bottom: 2px;
  transition: color 200ms var(--ease), border-color 200ms var(--ease);
}

.text-link:hover {
  color: var(--ui-accent-text);
  border-color: var(--ui-accent-line);
}

/* ------------------------------------------------------------- hero/shell -- */

.hero {
  padding: 148px 0 88px;
}

.hero::before {
  inset: 0;
  background-image: radial-gradient(var(--ui-grid) 1px, transparent 1px);
  background-size: 24px 24px;
  mask-image: radial-gradient(ellipse 90% 70% at 40% 0%, #000 0%, transparent 78%);
  -webkit-mask-image: radial-gradient(ellipse 90% 70% at 40% 0%, #000 0%, transparent 78%);
}

.hero::after {
  display: none;
}

.hero-grid {
  gap: 56px;
  align-items: center;
}

.eyebrow {
  gap: 8px;
  color: var(--ui-muted);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.14em;
}

.eyebrow::before {
  content: "";
  width: 24px;
  height: 1px;
  background: var(--ui-line-strong);
  order: -1;
}

.live-dot {
  background: var(--ui-accent-text);
}

.live-dot::after {
  border-color: var(--ui-accent-text);
}

.hero h1 {
  margin-top: 20px;
  font-family: var(--font-display);
  font-size: clamp(42px, 5.6vw, 74px);
  font-weight: 600;
  line-height: 1.03;
  letter-spacing: -0.035em;
  max-width: 640px;
  background: var(--ui-grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
}

.hero h1 em {
  color: inherit;
  -webkit-text-fill-color: transparent;
  box-shadow: none;
}

.hero-lede {
  max-width: 34em;
  margin-top: 24px;
  color: var(--ui-muted);
  font-size: 16px;
  line-height: 1.8;
}

.hero-actions {
  gap: 8px;
  margin-top: 32px;
}

.hero-meta {
  color: var(--ui-faint);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.02em;
}

.hero-facts {
  gap: 0;
  margin-top: 40px;
  border-top: 1px solid var(--ui-line);
  padding-top: 20px;
}

.hero-facts li {
  padding-right: 32px;
}

.hero-facts strong {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 500;
  letter-spacing: -0.02em;
}

.hero-facts span {
  color: var(--ui-faint);
  font-size: 11px;
  letter-spacing: 0.06em;
}

.hero-command {
  border: 1px solid var(--ui-line);
  border-radius: var(--r-2);
  background: var(--ui-surface);
}

/* ------------------------------------------------------------- flowboard -- */

.flowboard {
  border: 1px solid var(--dark-line);
  border-radius: var(--r-3);
  background: var(--dark);
  box-shadow: var(--ui-shadow);
  overflow: hidden;
}

.flowboard-bar {
  padding: 12px 16px;
  border-bottom: 1px solid var(--dark-line);
  background: transparent;
}

.flowboard-path {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--dark-muted);
}

.traffic i {
  width: 8px;
  height: 8px;
}

.flowboard-live {
  color: var(--dark-muted);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.flowboard-body {
  padding: 20px;
}

.flowboard-head {
  margin-bottom: 16px;
}

.micro-badge {
  border: 1px solid var(--dark-line);
  border-radius: 6px;
  color: var(--dark-muted);
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.12em;
}

.flow-steps {
  gap: 2px;
}

.flow-steps li {
  padding: 14px 12px;
  border: 1px solid transparent;
  border-radius: var(--r-1);
  transition: background-color 200ms var(--ease), border-color 200ms var(--ease);
}

.flow-steps li:hover {
  background: rgba(255, 255, 255, 0.03);
}

.flow-steps .is-focus {
  background: rgba(205, 242, 91, 0.1);
  border-color: rgba(205, 242, 91, 0.28);
}

[data-theme="dark"] .flow-steps .is-focus {
  background: rgba(205, 242, 91, 0.08);
  border-color: rgba(205, 242, 91, 0.24);
}

.flow-steps .is-focus .flow-text strong {
  color: var(--ui-accent-text);
}

.flow-steps .is-focus .flow-text span {
  color: var(--dark-text);
  opacity: 0.72;
}

.flow-no {
  color: var(--dark-muted);
  font-family: var(--font-mono);
  font-size: 10px;
}

.flow-text strong {
  color: var(--dark-text);
  font-size: 14px;
  font-weight: 600;
}

.flow-text span {
  color: var(--dark-muted);
  font-size: 12px;
}

.flow-chip {
  padding: 3px 7px;
  border: 1px solid var(--dark-line);
  border-radius: 6px;
  color: var(--dark-muted);
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: 0.04em;
}

.flow-steps .is-focus .flow-chip {
  border-color: rgba(205, 242, 91, 0.4);
  color: #cdf25b;
}

.hero-stamp {
  display: none;
}

/* --------------------------------------------------------- section rhythm -- */

.section {
  padding: 96px 0;
}

.section-alt {
  background: var(--ui-bg-2);
  border-top: 1px solid var(--ui-line);
  border-bottom: 1px solid var(--ui-line);
}

.section-head {
  max-width: 720px;
  margin-bottom: 48px;
}

.section-index {
  color: var(--ui-accent-text);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
}

.section-head h2,
.faq-intro h2,
.closing-copy h2 {
  margin-top: 12px;
  font-family: var(--font-display);
  font-size: clamp(30px, 4vw, 46px);
  font-weight: 600;
  line-height: 1.08;
  letter-spacing: -0.03em;
}

.section-lede {
  max-width: 62ch;
  margin-top: 16px;
  color: var(--ui-muted);
  font-size: 15.5px;
  line-height: 1.8;
}

/* ------------------------------------------------------------- download ---- */

.download-band {
  padding: 88px 0;
  background: var(--ui-bg-2);
  border-top: 1px solid var(--ui-line);
  border-bottom: 1px solid var(--ui-line);
}

.download-band-head {
  align-items: flex-end;
  margin-bottom: 32px;
}

.platform-grid {
  gap: 16px;
}

.platform-card {
  padding: 24px;
  border: 1px solid var(--ui-line);
  border-radius: var(--r-3);
  background: var(--ui-surface);
  box-shadow: none;
}

.platform-card:hover {
  transform: translateY(-2px);
  border-color: var(--ui-line-strong);
  box-shadow: var(--ui-shadow-sm);
}

.platform-icon {
  border: 1px solid var(--ui-line);
  border-radius: var(--r-1);
  background: var(--ui-surface-2);
  color: var(--ui-accent-text);
}

.platform-tag {
  color: var(--ui-faint);
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.06em;
}

.platform-copy strong {
  font-size: 16px;
  font-weight: 600;
}

.platform-copy p {
  color: var(--ui-muted);
  font-size: 13px;
}

.platform-action {
  border-top: 1px solid var(--ui-line);
  color: var(--ui-ink);
  font-size: 13px;
  font-weight: 500;
}

.platform-card:hover .platform-action {
  color: var(--ui-accent-text);
}

.download-strip-note {
  color: var(--ui-faint);
  font-size: 12.5px;
}

.download-strip-note a {
  color: var(--ui-muted);
  border-bottom: 1px solid var(--ui-line-strong);
}

.download-strip-note a:hover {
  color: var(--ui-ink);
}

/* ------------------------------------------------------------ home cards --- */

.home-highlights {
  gap: 16px;
}

.home-highlight {
  padding: 32px;
  border: 1px solid var(--ui-line);
  border-radius: var(--r-3);
  background: var(--ui-surface);
}

.home-highlight:hover {
  transform: translateY(-2px);
  border-color: var(--ui-line-strong);
  box-shadow: var(--ui-shadow-sm);
}

.home-highlight .mono {
  color: var(--ui-faint);
  font-size: 10.5px;
  letter-spacing: 0.12em;
}

.home-highlight h3 {
  margin-top: 16px;
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.home-highlight p {
  margin-top: 12px;
  color: var(--ui-muted);
  font-size: 14.5px;
  line-height: 1.75;
}

.home-highlight a {
  color: var(--ui-accent-text);
  font-size: 13.5px;
  font-weight: 500;
}

/* ---------------------------------------------------------------- closing -- */

.closing {
  padding: 96px 0;
  background: transparent;
}

.closing-inner {
  border: 1px solid var(--ui-line);
  border-radius: var(--r-4);
  background: var(--ui-surface);
  padding: 64px 48px;
  box-shadow: var(--ui-shadow-sm);
}

.closing-copy p {
  color: var(--ui-muted);
  font-size: 15px;
  line-height: 1.8;
}

.closing-actions {
  gap: 8px;
}

/* ----------------------------------------------------------------- footer -- */

.site-footer {
  padding: 64px 0 32px;
  background: transparent;
  border-top: 1px solid var(--ui-line);
  color: var(--ui-muted);
}

.footer-grid {
  gap: 32px;
  padding-bottom: 40px;
}

.footer-brand p {
  color: var(--ui-faint);
  font-size: 13px;
  line-height: 1.7;
  max-width: 30ch;
}

.footer-col h3 {
  color: var(--ui-faint);
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  margin-bottom: 12px;
}

.footer-col a {
  color: var(--ui-muted);
  font-size: 13.5px;
  padding: 4px 0;
  transition: color 200ms var(--ease);
}

.footer-col a:hover {
  color: var(--ui-ink);
}

.footer-bottom {
  border-top: 1px solid var(--ui-line);
  padding-top: 20px;
  color: var(--ui-faint);
  font-size: 11.5px;
}

.footer-bottom p {
  color: var(--ui-faint);
}

/* -------------------------------------------------------------- features --- */

.principle,
.flow-card,
.core-card,
.rule-card {
  padding: 28px;
  border: 1px solid var(--ui-line);
  border-radius: var(--r-3);
  background: var(--ui-surface);
  box-shadow: none;
}

.principle:hover,
.flow-card:hover,
.core-card:hover {
  border-color: var(--ui-line-strong);
  box-shadow: var(--ui-shadow-sm);
}

.principle-no,
.flow-card-no,
.core-kicker,
.number-item strong {
  font-family: var(--font-mono);
  color: var(--ui-accent-text);
}

.principle h3,
.flow-card h3,
.core-card h3 {
  font-size: 19px;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.principle p,
.flow-card p,
.core-card p {
  color: var(--ui-muted);
  font-size: 14px;
  line-height: 1.75;
}

.plain-list li,
.stack-list li {
  color: var(--ui-muted);
  font-size: 13.5px;
  line-height: 1.7;
}

.plain-list li::before {
  background: var(--ui-accent-text);
}

.feature-group {
  border: 1px solid var(--ui-line);
  border-radius: var(--r-3);
  background: var(--ui-surface);
  padding: 24px;
}

.feature-group:hover {
  border-color: var(--ui-line-strong);
}

/* numbers strip stays a dark band: never turn the items into cards */
.numbers {
  background: var(--dark);
  color: var(--dark-text);
  border-top: 1px solid var(--dark-line);
  border-bottom: 1px solid var(--dark-line);
}

.number-item {
  background: transparent;
  border: 0;
  border-left: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 0;
  padding: 2px 22px;
}

.number-item:first-child {
  border-left: 0;
  padding-left: 0;
}

.number-item strong {
  color: #cdf25b;
  font-family: var(--font-mono);
  font-size: clamp(24px, 2.4vw, 32px);
  font-weight: 500;
  letter-spacing: -0.02em;
}

.number-item span {
  color: var(--dark-muted);
  font-size: 10px;
  letter-spacing: 0.1em;
}

/* --------------------------------------------------------------- faq/arch -- */

.faq-item {
  border-bottom: 1px solid var(--ui-line);
}

.faq-item summary {
  padding: 20px 0;
  font-size: 15px;
  font-weight: 500;
}

.faq-item summary:hover {
  color: var(--ui-accent-text);
}

.faq-item summary i {
  border-color: var(--ui-line-strong);
}

.faq-answer {
  color: var(--ui-muted);
  font-size: 14px;
  line-height: 1.8;
}

.arch-node {
  border: 1px solid var(--ui-line);
  border-radius: var(--r-2);
  background: var(--ui-surface);
  padding: 16px;
}

.arch-node strong {
  font-size: 13.5px;
}

.arch-node small {
  color: var(--ui-muted);
  font-size: 11.5px;
}

.arch-kicker {
  color: var(--ui-faint);
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: 0.12em;
}

/* ------------------------------------------------------------ theme lab ---- */

.theme-choice {
  border: 1px solid var(--ui-line);
  border-radius: var(--r-2);
  background: var(--ui-surface);
  padding: 12px 14px;
}

.theme-choice:hover {
  border-color: var(--ui-line-strong);
}

.theme-choice.is-active {
  border-color: var(--ui-accent-line);
  background: var(--ui-accent-soft);
}

.theme-choice-text strong {
  font-size: 13.5px;
  font-weight: 600;
}

.theme-choice-text span {
  color: var(--ui-muted);
  font-size: 11.5px;
}

.theme-dots i {
  border-radius: 999px;
}

/* ------------------------------------------------------------- download ---- */

.install-card {
  border: 1px solid var(--ui-line);
  border-radius: var(--r-3);
  background: var(--ui-surface);
  padding: 28px;
}

.install-card:hover {
  border-color: var(--ui-line-strong);
  box-shadow: var(--ui-shadow-sm);
}

.command-row {
  border: 1px solid var(--ui-line);
  border-radius: var(--r-2);
  background: var(--ui-surface-2);
}

.command-row code,
.prompt {
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--ui-ink-2);
}

.copy-btn {
  border: 1px solid var(--ui-line);
  border-radius: 6px;
  color: var(--ui-muted);
  background: var(--ui-surface);
}

.copy-btn:hover {
  color: var(--ui-ink);
  border-color: var(--ui-line-strong);
}

.copy-btn.is-copied {
  color: var(--ui-accent-text);
  border-color: var(--ui-accent-line);
}

/* ------------------------------------------------------------ demo pages --- */

.demo-hub {
  padding: 132px 0 40px;
}

.demo-hub h1 {
  font-family: var(--font-display);
  font-size: clamp(34px, 4.4vw, 54px);
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.05;
  background: var(--ui-grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
}

.demo-hub-grid {
  gap: 40px;
  align-items: end;
}

.demo-hub-meta {
  gap: 32px;
}

.demo-hub-meta strong {
  font-family: var(--font-mono);
  font-size: 24px;
  font-weight: 500;
  letter-spacing: -0.02em;
}

.demo-hub-meta span {
  color: var(--ui-faint);
  font-size: 11px;
  letter-spacing: 0.06em;
}

.demo-tabs {
  gap: 4px;
  margin-top: 32px;
  border-bottom: 1px solid var(--ui-line);
}

.demo-tabs a {
  border: 0;
  border-radius: var(--r-1) var(--r-1) 0 0;
  padding: 10px 14px;
  color: var(--ui-muted);
  font-size: 13.5px;
}

.demo-tabs a span {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--ui-faint);
}

.demo-tabs a:hover {
  color: var(--ui-ink);
  background: var(--ui-surface-2);
}

.demo-tabs a[aria-current="page"] {
  color: var(--ui-ink);
  background: var(--ui-accent-soft);
}

.demo-tabs a[aria-current="page"] span {
  color: var(--ui-accent-text);
}

.demo-stage {
  padding: 32px 0 96px;
}

/* the product demo keeps its own light UI in both themes */
.demo-shell {
  border: 1px solid var(--ui-line);
  border-radius: var(--r-3);
  background: var(--ui-surface);
  box-shadow: var(--ui-shadow);
  overflow: hidden;
}

.demo-chrome {
  background: var(--ui-surface-2);
  border-bottom: 1px solid var(--ui-line);
  color: var(--ui-muted);
}

.demo-chrome-path {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--ui-faint);
}

.demo-chrome-badge {
  color: var(--ui-muted);
  font-size: 10px;
}

.demo-body {
  background: #ffffff;
  color: #0f172a;
}

.demo-stage-note {
  color: var(--ui-faint);
  font-size: 12.5px;
  line-height: 1.75;
}

.demo-stage-note a {
  color: var(--ui-muted);
  border-bottom: 1px solid var(--ui-line-strong);
}

.demo-fineprint {
  border: 1px solid var(--ui-line);
  border-radius: var(--r-2);
  background: var(--ui-surface);
}

.demo-fineprint summary {
  color: var(--ui-muted);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
}

.demo-fineprint li {
  color: var(--ui-muted);
  font-size: 13px;
}

/* ------------------------------------------------------------ page hero ---- */

.page-hero {
  padding: 132px 0 56px;
  border-bottom: 1px solid var(--ui-line);
  background: var(--ui-bg);
}

.page-hero::before {
  display: none;
}

.page-hero h1 {
  margin-top: 16px;
  font-family: var(--font-display);
  font-size: clamp(38px, 5.2vw, 60px);
  font-weight: 600;
  line-height: 1.05;
  letter-spacing: -0.035em;
}

.page-hero h1 em {
  color: var(--ui-accent-text);
  font-style: normal;
}

.page-hero .section-lede {
  max-width: 56ch;
  color: var(--ui-muted);
  font-size: 16px;
  line-height: 1.8;
}

.page-hero-aside {
  border: 1px solid var(--ui-line);
  border-radius: var(--r-3);
  background: var(--ui-surface);
  padding: 24px;
}

.page-hero-aside > .mono {
  color: var(--ui-faint);
  font-size: 10px;
  letter-spacing: 0.14em;
}

.page-hero-aside dl div {
  border-top: 1px solid var(--ui-line);
}

.page-hero-aside dt {
  color: var(--ui-faint);
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.page-hero-aside dd {
  color: var(--ui-ink);
  font-size: 12.5px;
}

/* themes page opens with a section, not a hero */
.themes-section {
  padding-top: 132px;
}

/* download status banner */
.download-status {
  border: 1px solid var(--ui-line);
  border-radius: var(--r-2);
  background: var(--ui-surface);
  padding: 14px 16px;
}

.download-status[data-state="ready"] {
  border-color: var(--ui-accent-line);
  background: var(--ui-accent-soft);
}

.download-status[data-state="ready"] .live-dot {
  background: var(--ui-accent-text);
}

.download-status[data-state="error"] {
  border-color: var(--ui-line-strong);
  background: var(--ui-surface-2);
}

.download-status strong {
  font-size: 13px;
}

.download-status span {
  color: var(--ui-muted);
  font-size: 12px;
}

/* ---------------------------------------------------------------- 404 ------ */

.not-found {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 120px 24px 80px;
  background: var(--ui-bg);
}

.not-found-inner {
  width: min(560px, 100%);
  border: 1px solid var(--ui-line);
  border-radius: var(--r-4);
  background: var(--ui-surface);
  padding: 48px;
  box-shadow: var(--ui-shadow);
}

.not-found h1 {
  font-family: var(--font-display);
  font-size: clamp(40px, 8vw, 68px);
  font-weight: 600;
  line-height: 1.02;
  letter-spacing: -0.035em;
  margin: 16px 0 0;
  background: var(--ui-grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
}

.not-found h1 em {
  color: inherit;
  font-style: normal;
  -webkit-text-fill-color: transparent;
}

.not-found p {
  margin-top: 16px;
  color: var(--ui-muted);
  font-size: 14px;
  line-height: 1.8;
}

.not-found-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 28px;
}

@media (max-width: 520px) {
  .not-found-inner {
    padding: 28px 24px;
  }
}

/* ----------------------------------------------------------- responsive --- */

@media (max-width: 1040px) {
  .site-header {
    padding: 0 16px;
    top: 12px;
  }

  .site-header .header-inner {
    width: 100%;
    padding: 6px 6px 6px 14px;
    gap: 8px;
  }

  .site-nav {
    display: none;
  }

  .header-actions {
    margin-left: auto;
  }

  .ghost-link {
    display: none;
  }

  /* full height panel instead of a dropdown */
  .site-header.is-open .site-nav {
    position: fixed;
    inset: 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: stretch;
    gap: 4px;
    margin: 0;
    padding: 96px 24px 40px;
    background: var(--ui-bg);
    border: 0;
    box-shadow: none;
    z-index: -1;
  }

  .site-header.is-open .site-nav a {
    padding: 16px 0;
    border-bottom: 1px solid var(--ui-line);
    border-radius: 0;
    font-size: 22px;
    font-weight: 600;
    letter-spacing: -0.02em;
    background: transparent;
  }

  .site-header.is-open .site-nav a:hover {
    color: var(--ui-accent-text);
  }

  .site-header.is-open .site-nav .nav-github {
    color: var(--ui-muted);
    border-bottom: 0;
  }

  .hero {
    padding: 120px 0 64px;
  }

  .page-hero {
    padding: 112px 0 48px;
  }

  .themes-section {
    padding-top: 112px;
  }

  .hero-grid {
    gap: 48px;
  }

  .demo-hub {
    padding: 112px 0 32px;
  }

  .closing-inner {
    padding: 48px 32px;
  }
}

@media (max-width: 720px) {
  .wrap {
    width: min(var(--wrap), calc(100% - 32px));
  }

  .site-header .header-inner {
    min-height: 50px;
  }

  .brand-text small {
    display: none;
  }

  .lang-switch {
    min-width: 30px;
    padding: 0 6px;
  }

  .btn-small {
    padding: 7px 10px;
    font-size: 12px;
  }

  .section,
  .download-band,
  .closing {
    padding: 64px 0;
  }

  .hero {
    padding: 104px 0 56px;
  }

  .page-hero {
    padding: 96px 0 40px;
  }

  .themes-section {
    padding-top: 96px;
  }

  .hero h1 {
    font-size: 38px;
  }

  .hero-lede {
    font-size: 15px;
  }

  .hero-facts strong {
    font-size: 20px;
  }

  .section-head {
    margin-bottom: 32px;
  }

  .home-highlight,
  .principle,
  .flow-card,
  .core-card,
  .install-card,
  .platform-card {
    padding: 22px;
  }

  .closing-inner {
    padding: 36px 24px;
  }

  .demo-hub h1 {
    font-size: 32px;
  }

  .demo-tabs {
    overflow-x: auto;
    flex-wrap: nowrap;
  }

  .demo-tabs a {
    white-space: nowrap;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}